DE60111281T2 - STABILIZED INFRARED ABSORBING CYANING ELEMENT FOR LASER COLOR TRANSFER - Google Patents

Description

The The present invention relates to a stabilizer for an infrared-absorbing Cyanine colorant for use in colorant donor elements Laser transmission. The infrared colorants are especially in laser colorant transfer systems suitable for the digital color grid checking are provided.

Around the appearance of a (photographic) holding bonus image by means of ink printing on paper approximately one uses oneself in the commercial printing industry a so-called raster printing process. To be printed in halftone Color density gradations are created by making dot patterns or areas of different colors Size though same color density, rather than the color density continuously to change, as is the case in photographic imaging.

It There is a significant commercial need to produce one colored proof image before production of the print run. It is desirable that the color proof at least the details and the color gamut of the represents exactly what is printed on the press. In many cases it is also desirable that the color proof the image quality and the raster pattern of the represents exactly what is printed on the press. In the processes, for producing an ink-printed, full-color image necessary, a proof is also required to ensure accuracy to control the color separation data that make up the three or more Printing plates or impression cylinder are made. Conventionally for this Color separation proofs High contrast photographic silver halide offset systems or silver halide-free photosensitive systems used, which require numerous exposure and processing steps, before a finished full-color image is available.

The Dyes used in the printing industry are insoluble pigments. Due to their pigment properties are the spectrophotometric Curves of printing inks often unusual clearly on the bathochromic or hypsochromic side. This can in color proofing systems Cause problems using colorants instead of pigments become. It is very difficult to match the hue of a given printing ink to hit a single colorant.

• a) Erzeugen einer Menge von elektrischen Signalen, die die Form und die Farbskala eines Originalbildes darstellen;
• b) Berühren eines Farbmittelgeberelements, das einen Träger mit einer darauf angeordneten Farbmittelschicht und einem infrarotabsorbierenden Material umfasst, mit einem ersten Farbmittelempfangselement, das einen Träger und eine darauf angeordnete polymere Farbmittelbildempfangsschicht umfasst.
• c) Verwenden von Signalen zur bildweisen Erwärmung des Farbmittelgeberelements mithilfe eines Diodenlasers, wodurch ein Farbmittelbild auf das erste Farbmittelempfangselement übertragen wird; und
• d) Rückübertragen des Farbmittelbildes auf ein zweites Farbmittelbildempfangselement, das das gleiche Substrat wie das gedruckte Farbbild aufweist.

US-A-5,126,760 describes a method of producing a direct digital halftone color proof of an original image on a colorant-receiving element. The proof can be used to display a color image printed on a printing machine. The method described therein comprises:

• a) generating a set of electrical signals representing the shape and color gamut of an original image;
• b) contacting a colorant donor element comprising a support having a colorant layer and an infrared absorbing material disposed thereon with a first colorant-receiving element comprising a support and a polymeric colorant image-receiving layer disposed thereon.
• c) using signals to imagewise heat the colorant donor element using a diode laser, thereby transferring a colorant image to the first colorant receiving element; and
• d) retransferring the colorant image to a second colorant image-receiving element having the same substrate as the printed color image.

In The method described above, several color donors used to complete a To create range of colors in the proof. For example for a Full color proof used four colors, namely usually teal, purple, yellow and black.

aid of the aforementioned method, the image colorant is transferred by the colorant donor element that the infrared absorbing Contains material, with the diode laser for volatilization of the colorant heated is, wherein the diode laser beam with a set of signals modulated is that represent the shape and color of the original image, so that the colorant so heated is that it is only volatilized in those areas where its Presence on the dye receiving layer for reconstruction of the original image necessary is.

For high-quality color proofing in the printing industry, you must be able to meet the proofing ink references of the International Prepress Proofing Association. These ink references are density patches made with standard four-color process inks and are known as SWOP ^® color standards (Specifications Web Offset Publications). For more information on the color measurement of inks for web offset proofing, see Advances in Printing Science and Technology, Proceedings of the 19th International Conference on Printing Research Institutes, Eisenstadt, Austria, June 1987, JT Ling and R. Warner, page 55.

infrared Colorants are used in colorant donor elements for laser colorant transfer for the purpose of absorbing laser energy and converting the Radiation energy in heat energy used a colorant transfer to effect on a receiving element. One when using infrared colorants The known problem is that these colorants often a have some absorption in the visible spectrum. If a part or transfer all of the infrared colorant together with the colorant This absorption can be the color purity or the color tone of the transferred Affect image colorant.

US-A-5,972,838 describes infrared absorbing dyes for laser dye transfer. However, there is a problem with using these dyes high humidity on. When the dye donor element in a Chamber with 38 ° C / 90% rel. Humidity for Stored for 48 hours, the absorption at 810 nm decreases by 30-40%. This is due to a shift in the absorption of the IR dye to a shorter one wavelength which is probably due to aggregation. The dye will not destroyed, since it can be demonstrated by HPLC analysis that most of the Dye is still present.

Of the present invention is based on the object, a Farbmittelgeberelement for the to provide laser-induced thermal dye transfer, which contains a stabilizer and is usable under conditions of high humidity and the maximum absorption capacity of the infrared absorbing cyanine colorant at the wavelength of Retains laser emission.

worin: jeweils W unabhängig voneinander für die Atome steht, die zur Bildung eines optionalen, 6-gliedrigen aromatischen Rings notwendig sind;
jeweils X unabhängig für Schwefel oder C(CH₃)₂ steht;
jeweils Y unabhängig für eine Alkylengruppe mit 2 bis 5 Kohlenstoffatomen steht;
Z für Chlor oder eine Alkylsulfonylgruppe mit 1 bis 4 Kohlenstoffatomen steht; und
jeweils R unabhängig für eine Alkylgruppe mit 1 bis 6 Kohlenstoffatomen steht; und
wobei die Farbmittelschicht auch einen Stabilisator enthält, der ein Phenoxyharz, ein Copolymer von Vinylchlorid/Vinylacetat-Maleinanhydrid oder ein Copolymer von Styrol/4-Vinylpyridin umfasst.These and other objects are achieved by the present invention which relates to a colorant donor element for the laser thermal transfer process comprising a support having a colorant layer thereon and containing a colorant dispersed in a binder, the colorant layer being associated with an infrared-absorbing cyan colorant having at least two sulfonic acid groups, wherein the cyanine colorant has the formula:

wherein: each W independently represents the atoms necessary to form an optional 6-membered aromatic ring;
each X is independently sulfur or C (CH ₃ ) ₂ ;
each Y is independently an alkylene group having 2 to 5 carbon atoms;
Z is chlorine or an alkylsulfonyl group having 1 to 4 carbon atoms; and
each R independently represents an alkyl group having 1 to 6 carbon atoms; and
wherein the colorant layer also contains a stabilizer comprising a phenoxy resin, a copolymer of vinyl chloride / vinyl acetate-maleic anhydride or a copolymer of styrene / 4-vinylpyridine.

By Use of the invention is the maximum absorption capacity of the infrared absorbing cyanine colorant at the wavelength of Preserve laser emission under conditions of high humidity.

As previously mentioned, the stabilizers useful in the invention include a phenoxy resin, a copolymer of vinyl chloride / vinyl acetate-maleic anhydride, or a copolymer of styrene / 4-vinylpyridine. The usable in the invention include phenoxy PKHH ^® of phenoxy Specialties. In a preferred embodiment of the invention, the stabilizer is present in an amount of from 0.02 g / m ² to 0.1 g / m ² , preferably from 0.025 g / m ² to 0.05 g / m ² . In another preferred embodiment of the invention, the stabilizer is a phenoxy resin.

In a preferred embodiment R is n-butyl for increasing the solubility of the cyanine colorant in organic solvents and in the coated polymer colorant complex.

Examples of sulfonic acid containing cyanine IR colorants useful in the invention include the following Amine salts:

The donor elements may optionally include between the image colorant or pigment layer and the support a substrate or barrier layer substrate as described in US-A-4,695,288 and US-A-4,737,486 and may contain layers of organotitanates, silicates or aluminates, etc. Preferably a layer is used from tetrabutyl titanate, the (Du Pont Corp.) is available as Tyzor TBT ^® commercially.

As colorants, pigments and dyes are usable in the invention. Pigments useful in the invention include organic pigments such as metal phthalocyanines such as copper phthalocyanine, quinacridones, epindolidiones, rubies F6B (CI No. Pigment 184); Cromophtal ^® Yellow 3G (CI No. Pigment Yellow 93).; Hostaperm ^® Yellow 3G (CI No. Pigment Yellow 154).; Monastral ^® Violet R (. CI No. Pigment Violet 19); 2,9-dimethylquinone cridone (CI No. Pigment Red 122); Indofast ^® Brilliant Scarlet R6300 (CI No. Pigment Red 123).; Quindo Magenta RV 6803; Monstral ^® Blue G (CI No. Pigment Blue. 15); Monstral ^® Blue BT 383D (CI No. Pigment Blue. 15); Monstral ^® Blue G BT 284D (CI No. Pigment Blue. 15); Monstral ^® Green GT 751D (CI no. Pigment Green 7) or in US-A-5,171,650 or US-A-5,672,458, or materials described US-A-5,516,622.

Dyes usable in the present invention inter alia include anthraquinone dyes, eg, Sumikaron Violet RS ^® (of Sumitomo Chemical Co., Ltd.), Dianix Fast Violet 3R-FS ^® (of Mitsubishi Chemical Industries, Ltd.), and Kayalon Polyol Brilliant Blue N BGM ^® and KST Black 146 ^® (by Nippon Kayaku Co., Ltd.); Azo dyes such as Kayalon Polyol Brilliant Blue BM ^®, Kayalon Polyol Dark Blue 2BM ^® and KST Black KR ^® (by Nippon Kayaku Co., Ltd.), Sumikaron Diazo Black SG ^® (of Sumitomo Chemical Co., Ltd.) and Miktazol Black ^SGH® (from Mitsui Toatsu Chemicals, Inc.); Direct dyes such as Direct Dark Green B ^® (of Mitsubishi Chemical Industries, Ltd.) and Direct Brown M ^® and Direct Fast Black D ^® (of Nippon Kayaku Co. Ltd.); Acid dyes such as Kayanol Milling Cyanine SR ^® (of Nippon Kayaku Co. Ltd.); Basic dyes such as Sumiacryl Blue 6G ^® (of Sumitomo Chemical Co., Ltd.), and Aizen Malachite Green ^® (by Hodogaya Chemical Co., Ltd.); or in U.S. Patent Nos. 4,541,830; US-A-4,698,651; US-A-4,695,287; US-A-4,701,439; US-A-4,757,046; US-A-4,743,582; No. 4,769,360 and US Pat. No. 4,753,922. The aforementioned dyes are single or usable in combination. Combinations of pigments and / or dyes are also useful.

The colorants used in the present invention are useful with an order of 0.02 to 1 g / m ² .

The method for producing an image with those used in the present invention, colorant or pigment-donor elements has been described in US-A-5,126,760 and is ^® in commercial deliverable laser thermal proofing systems in use, such ^® at the Kodak Approval system or the Creo Trendsetter Spectrum System , Usually, a receiving sheet is mounted on a rotating drum, after which the individual cyan, magenta, yellow and black donor elements are clamped, whereby the image is transmitted for each color by the imagewise exposure of the laser beam through the back of the donor element.

The colorants in the colorant donor element of the present invention are dispersed in a polymeric binder such as cellulose derivative, eg, cellulose acetate hydrogen phthalate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose triacetate, or any of the materials described in US-A-4,700,207; polyvinyl butyrate; Copolymers of maleic anhydride with vinyl ethers, such as methyl vinyl ether; Polycyanoacrylates, polycarbonate; Poly (vinyl acetate); Polystyrene-co-acrylonitrile); Polysulfone or poly (phenylene oxide). The binder is usable with an order of 0.1 to 5 g / m ² . Some of the stabilizers described above can also serve as binders, so that a separate binder is not necessary.

The Colorant layer of the colorant donor element may be applied to the support or by using a printing technique such as gravure printing, to be printed.

When carrier for the Inventive Farbmittelgeberelement Any material is usable provided it is dimensionally stable and opposite the heat development of the laser resistant. Such materials are i.a. Polyesters such as poly (ethylene terephthalate); polyamides; polycarbonates; Cellulose esters, such as cellulose acetate; Fluoropolymers such as poly (vinylidene fluoride) or poly (tetrafluoroethylene-co-hexafluoropropylene); Polyethers such as polyoxymethylene; polyacetals; Polyolefins, such as polystyrene, Polyethylene, polypropylene or methylpentene polymers and polyimides, such as polyimideamides and polyetherimides. The carrier generally has a thickness from 5 to 200 μm.

The receiving element used with the donor element of the invention normally comprises a support having a colorant-image-receiving layer disposed thereon. The support may be a transparent film such as a poly (ether sulfone), a polyimide, a cellulose ester such as a cellulose acetate, a poly (vinyl alcohol-co-acetal) or a poly (ethylene terephthalate). The support for the dye-receiving element may also be reflective such as baryta-coated paper, polyethylene-coated paper, an ivory paper, a condenser paper or a synthetic paper such as DuPont Tyvek ^®. Pigmented supports such as white polyester (transparent polyester with white pigment incorporated therein) are also usable.

The image-receiving layer may further include, for example, a polycarbonate, a polyurethane, a polyester, poly (vinyl chloride), polystyrene-coacrylonitrile), polycaprolactone, a poly (vinyl acetal) such as poly (vinyl alcohol-cobutyral), poly (vinyl alcohol-cobenzal), poly (vinyl alcohol -Coacetal) or mixtures thereof. The image-receiving layer may be present in any amount effective for the intended purpose. In general, good results are achievable at a concentration of 1 to 5 g / m ² .

As already mentioned, serve the colorant donor elements according to the invention to a colorant transfer image to customize. Such a method comprises imagewise heating a Farbmittelgeberelements, as described above, and the transfer a colorant image on a receiving element to the colorant transfer image manufacture.

The Inventive Farbmittelgeberelement is usable in sheet form or as continuous web or continuous roll. If a continuous web or continuous roll is used, it can only the colorant can be arranged as described above, or it can changing areas of different, different colorants or Colorant combinations may be arranged, such as sublimable cyan and / or Yellow and / or black or other dyes. Such colorants are described in US-A-4,541,830. Thus, one, two, three or four-color elements (or a higher number) in the scope of the present invention.

For transmission of colorants of the colorant donor elements according to the invention a laser is used. The laser is preferably a diode laser because it offers significant benefits in terms of size, cost, Stability, Reliability, Durability and modulability. Laser for transmission of colorants from donor elements used in the invention are commercially available. For example, the SDL-2420-H2 laser is from Spectra Diode Labs or the SLD 304 V / W laser from Sony Corporation usable.

One Thermal printer using the laser described above to a Forming image on a thermal printing medium is disclosed in US-A-5,268,708 described and claimed.

In a separate layer over the colorant layer of the colorant donor element in the previously described Laser methods are spacers usable to the colorant donor element from the colorant-receiving element during colorant transfer to separate and thereby the uniformity and density of the transferred Increase picture. This invention is described in more detail in US-A-4,772,582. Alternatively, the spacers are in the receiving layer of the receiving element as described in US-A-4,876,235. The spacers can, if desired, be coated with a polymeric binder.

The Use of a receive intermediate element with subsequent retransmission to a second receiving element is also usable in the invention, as in US-A-5,126,760 described. A plurality of different substrates can be used around the color proof (the second receiving element), preferably the same Substrate has, like that for used the print run in the printing press. This receive intermediate element let yourself thus for an efficient colorant absorption without greasing or crystallization optimize the colorant.

Optional Can the paper with an image receiving or colorant blocking layer prelaminated or precoated in a dual laminate process as described in US-A-5,053,381. The reception sheet can also the actual paper proof material or a simulation of it on which an optional laminate to protect the finished image is applied.

Examples of substrates that can be used for the second receiving element (color proof) include the following: Flo Kote Cover ^® (SD Warren Co.), Champion Textweb ^® (Champion Paper Co.), Quintessence Gloss ^® (Potlatch Inc.) Vintage Gloss ^® (Potlatch Inc.), Khrome Kote ^® (Champion Paper Co.), Consolith Gloss ^® (Consolidated Papers Co.), Ad-proof Paper ^® (Appleton Papers, Inc.) and Mountie mat ^® (Potlatch Inc.) ,

As previously mentioned, For example, the colorant image after generation on a first colorant-receiving element be transferred back to a second colorant receiving element. This can For example, by placing the two receiving elements between performs two heating rollers. There are also other methods for retransferring the colorant image applicable, such as the use of a hot plate, applying with pressure and heat, external heating etc.

As previously mentioned, When making a color proof, a set of electrical Signals generated for the shape and color of an original image are representative. This can be, for example by scanning an original image, by filtering the original image Image for separation into the desired additive basic colors, i.e. red, blue and green, and converting the light energy into electrical energy. The electrical Signals are then modified by computer to get the color separation data to produce, which serve to produce a raster color proofs. Instead of to scan an original object to generate the electrical signals, can the signals are also generated by computer. This method becomes more detailed in Graphic Arts Manual, edited by Janet Field, Arno Press, New York 1980 (p. 358ff).

• a) ein Farbmittelgeberelement, wie zuvor beschrieben, und
• b) ein Farbmittelempfangselement, wie zuvor beschrieben,

wobei sich das Farbmittelempfangselement in übergeordneter Beziehung zu dem Farbmittelgeberelement befindet, so dass sich die Farbstoffschicht des Geberelements in Kontakt mit der Farbmittelbildempfangsschicht des Empfangselements befindet.A thermal colorant transfer arrangement according to the invention comprises:

• a) a colorant donor element, as described above, and
• b) a colorant-receiving element, as described above,

wherein the colorant-receiving element is in superior relationship to the colorant-donor element such that the dye layer of the donor element is in contact with the colorant-image-receiving layer of the receiver element.

The aforementioned composite of these two elements may be preassembled as an integrated unit if a monochrome image is to be generated. For this purpose, the two elements on their Rän be temporarily arrested. After transfer, the colorant-receiving element is separated to expose the colorant transfer image.

If a three-color image is to be generated, the previously described Arrangement three times with different colorant donor elements educated. After transferring of the first colorant, the elements are separated from each other. A second colorant donor element (or other area of the Donor element with a different colorant range) is then in Registration brought with the colorant receiving element, and the Process is repeated. The third color will work in the same way generated. With the colorant donor element according to the invention can also be made a four-color image.

The The following examples serve to illustrate the invention.

example 1

The following Dyes were used in this example:

Gelbfarbstoff A

Yellow dye A

Gelbfarbstoff B

Yellow dye B

Cyaninfarbstoff C (US-A-5,972,838) (Tributylammoniumsalz von IR-1)

Cyanine dye C (US-A-5,972,838) (tributylammonium salt of IR-1)

Control element 1

To a 100 μm poly (ethylene terephthalate) support was coated a dye layer comprising: 0.072 g / m ² yellow dye A, see above, 0.013 g / m ² yellow dye B, see above, 0.027 g / m ² cyanine dye C in a cellulose acetate propionate binder (CAP 480-20 from Eastman Chemical Company), 0.16 g / m ^{2 of} a solvent mixture of diethyl ketone and 1-methoxy-2-propanol (55/45 weight ratio).

Control element 2

This element corresponded to control element 1 with the difference that it also contained 0.027 g / m ^{2 of} polyvinylpyridine.

Control element 3

This element corresponded to the control element 1 with the difference that it also contained 0.027 g / m ² polyvinylpyrrolidone.

Control element 4

This element was the same as control element 1 except that it also contained 0.027 g / m ^{2 of} Chlorowax 40 (Occidental Chemical Corp.).

Control element 5

This element corresponded to control element 1 with the difference that it also contained 0.027 g / m ^{2 of} poly-N, N-dimethylacrylamide.

Inventive element 1

This element was the same as Control Element 1 except that it also contained 0.027 g / m ² of phenoxy resin PKHH Phenoxy Specialties of ^®.

Inventive element 2

This element corresponded to Control 1 except that it also contained 0.027 g / m ^{2 of} a copolymer of vinyl chloride / vinyl acetate / maleic anhydride.

Inventive element 3

This element was similar to Control 1 except that it also contained 0.027 g / m ^{2 of} a 50/50 styrene / 4-vinylpyridine copolymer.

test

The transmission spectrum between 400 and 1000 nm of the above elements was on a Hewlett-Packard Diode array spectrophotometer 8453 before and after incubation in one Chamber at 38 ° C / 90% rel. Humidity for Recorded for 20 hours. The percentage absorption loss at 802 nm (λ max of the dye) was calculated and reported in Table 1 below. A lower level of dye loss is preferred.

Table 1

The The above results show that elements 1-3, the containing the stabilizers used in the invention, a lower percent dye loss than the control elements 1-5.

Example 2

Inventive element 4

This element was the same as Element 1, except that the amount of PKHH was 0.054 g / m ² .

Inventive element 5

This element was the same as Element 2, except that the amount of the copolymer was 0.054 g / m ² .

Inventive element 6

This element was the same as Element 3 except that the amount of the copolymer was 0.054 g / m ² .

test

The Elements as well as control element 1 were tested as in Example 1, with the difference that the elements were incubated for 96 hours. The following results were achieved:

Table 2

The The above results show that elements 4-6, the containing the stabilizers used in the invention, a lower percent dye loss than the control element 1 had.

Example 3

The following Dyes were used in this example:

Purpurrotfarbstoff D

Purple Dye D

Purple Dye E

Gelbfarbstoff F

Yellow dye F

Magenta-control transmitter element 6

To a 100 μm poly (ethylene terephthalate) support was coated a dye layer comprising: 0.057 g / m ² magenta dye D, see above, 0.032 g / m ² magenta dye E, see above, 0.0098 g / m ² yellow dye F and 0.027 g / m ² cyanine dye C in a cellulose acetate propionate binder (CAP 480-20 from Eastman Chemical Company), 0.16 g / m ^{2 of} a mixed solvent of diethyl ketone and 1-methoxy-2-propanol (55/45 weight ratio).

Inventive element 7

This element corresponded to control element 6 except that the amount of CAP was 0.106 g / m ² and that the coating contained 0.053 g / m ^{2 of} stabilizer phenoxy resin PKHH.

The The above elements were tested as in Example 2. There were achieved the following results:

Table 3

The The above results show that the element 7, which is the one in the Stabilizer used contained a lower percentage Dye loss as the control element 6 had.

Example 4

The following Dyes were used in this example:

Blaugrünfarbstoff G

Cyan dye G

Blaugrünfarbstoff H

Cyan dye H

Cyan dye-control transmitter element 7

To a 100 μm poly (ethylene terephthalate) support was coated a dye layer comprising: 0.024 g / m ² cyan dye G, see above, 0.056 g / m ² cyan dye H, see above, 0.027 g / m ² cyan dye C in a cellulose acetate propionate binder (CAP 480-20 from Eastman Chemical Company), 0.16 g / m ^{2 of} a solvent mixture of diethyl ketone and 1-methoxy-2-propanol (55/45 weight ratio).

Inventive element 8th

This element corresponded to control element 7 except that the amount of CAP was 0.106 g / m ² and that the coating contained 0.053 g / m ^{2 of} stabilizer phenoxy resin PKHH.

The The above elements were tested as in Example 2. There were achieved the following results:

Table 4

The The above results show that the element 8, which has the in the Stabilizer used contained a lower percentage Dye loss as the control element 7 had.

Claims (10)

A colorant donor element for the laser thermal transfer process comprising a support having a colorant layer thereon and containing a colorant dispersed in a binder, wherein the colorant layer is associated with an infrared-absorbing cyanine colorant having at least two sulfonic acid groups, the cyanine colorant having the formula:

wherein: each W independently represents the atoms necessary to form an optional 6-membered aromatic ring; each X is independently sulfur or C (CH ₃ ) ₂ ; each Y is independently an alkylene group having 2 to 5 carbon atoms; Z is chlorine or an alkylsulfonyl group having 1 to 4 carbon atoms; and each R independently represents an alkyl group having 1 to 6 carbon atoms; and wherein the colorant layer also contains a stabilizer comprising a phenoxy resin, a copolymer of vinyl chloride / vinyl acetate-maleic anhydride or a copolymer of styrene / 4-vinylpyridine. A colorant-donor element according to claim 1, wherein the stabilizer is present in an amount of 0.02 g / m ² to 0.1 g / m ² . A colorant delivery element according to claim 1, wherein the Stabilizer is a phenoxy resin. A colorant donor element according to claim 1, wherein X is C (CH ₃ ) ₂ and Y is (CH ₂ ) ₃ . A colorant donor element according to claim 1, wherein Z is chloro or methylsulfonyl. A dye donor element according to claim 1, wherein R is n-butyl stands. A colorant delivery element according to claim 1, wherein said Colorant is a dye. A colorant delivery element according to claim 1, wherein said Colorant is a pigment. A method of forming a laser thermal transfer image comprising imagewise heating a colorant donor element using a laser comprising a support having thereon a colorant layer containing a colorant dispersed in a polymeric binder, and transferring a dye image to a colorant receiving element to form the colorant donor element A colorant transfer image wherein the colorant layer is associated with an infrared-absorbing cyanine colorant having at least two sulfonic acid groups, and wherein the cyanine colorant has the formula:

wherein: each W independently represents the atoms necessary to form an optional 6-membered aromatic ring; each X is independently sulfur or C (CH ₃ ) ₂ ; each Y is independently an alkylene group having 2 to 5 carbon atoms; Z is chlorine or an alkylsulfonyl group having 1 to 4 carbon atoms; and each R independently represents an alkyl group having 1 to 6 carbon atoms; and wherein the colorant layer also contains a stabilizer comprising a phenoxy resin, a copolymer of vinyl chloride chloride / vinyl acetate-maleic anhydride or a copolymer of styrene / 4-vinylpyridine. A laser thermal transfer assembly comprising: a) a colorant-donor element comprising a support having a colorant layer thereon and containing a colorant dispersed in a polymeric binder, and b) a colorant-receiving element comprising a support having a colorant-image-receiving layer disposed thereon Colorant-receiving element is in a superordinate relationship to the colorant-donor element such that the colorant layer is in contact with the colorant-image-receiving layer, wherein the colorant layer is associated with an infrared-absorbing cyanine colorant having at least two sulfonic acid groups, and wherein the cyanine colorant has the formula:

wherein: each W independently represents the atoms necessary to form an optional 6-membered aromatic ring; each X is independently sulfur or C (CH ₃ ) ₂ ; each Y is independently an alkylene group having 2 to 5 carbon atoms; Z is chlorine or an alkylsulfonyl group having 1 to 4 carbon atoms; and each R independently represents an alkyl group having 1 to 6 carbon atoms; and wherein the colorant layer also contains a stabilizer comprising a phenoxy resin, a copolymer of vinyl chloride / vinyl acetate-maleic anhydride or a copolymer of styrene / 4-vinylpyridine.